DGB 2: Programs and Data

← Digital Literacy – Year 2

Programs can only process text, numbers, images and sounds when these are represented as data in an agreed form. This chapter connects familiar media with the computing idea of encoding: characters, numbers, pixels and measurements are stored so that programs can read, change and output them.

Curriculum reference

Area	Classification
Competence area	Production
Perspectives	Technical perspective (T)
Focus	How programs store and process data
Competence	Investigate simple data representations and explain how programs store inputs as data, process them according to rules and produce outputs.

Learning objectives

Students can:

distinguish information from data;
explain that programs store data using defined representations;
describe text as a sequence of encoded characters;
distinguish numerical values from digits stored as text;
model pixel images as grids of colour values;
understand sound in simplified terms as a sequence of digital measurements;
explain variables as named storage locations or assignments in programs;
distinguish simple data types such as number, text and Boolean value;
connect input, processing, storage and output;
apply simple rules to stored values;
create small coding systems and test whether they are unambiguous;
recognise errors caused by unsuitable data types or ambiguous encoding.

Learning content

Information becomes data

People interpret meaning; computers initially process structured data. The word ‘Hello’, the number 25, a photo and a sound each need a technical representation. Agreed formats and coding rules allow programs to interpret the same data consistently.

Text as a sequence of characters

For a program, text can be represented as a sequence of characters. Character encodings such as Unicode assign identifiers to letters, digits and many other symbols. The important idea is that visible characters have an internal representation.

Number or text?

The value 25 used in a calculation is different from the characters ‘2’ and ‘5’ stored as text. A program can add numbers, while text may be joined or searched. Choosing the correct data type affects which operations make sense.

Pixel images as data

A raster image can be modelled as a grid. Each pixel stores a colour value. More pixels can provide more detail but also increase the amount of data. Editing an image changes pixel values or the way they are interpreted.

Sound as digital measurements

Digital audio can be understood as a sequence of measured values taken over time. More detailed representation can require more data. This simplified model explains why sound can be stored, copied and processed by software.

Variables and data types

A variable gives a name to a value that a program needs. Values can change while a program runs. Simple data types include numbers, text and Boolean values such as true/false. The data type helps determine which operations are possible.

Processing according to rules

Programs transform data according to instructions: they can calculate, compare, join, sort, count or choose between alternatives. Input provides data, processing applies rules, storage keeps values, and output presents or sends results.

Classroom activities

Translate information into symbols

Invent a small code for a set of classroom messages and test whether everyone can decode it.

Expected outcome: An unambiguous coding system.

Investigate text as characters

Split words and short sentences into individual characters and compare letters, spaces, punctuation and symbols.

Expected outcome: Understanding of character sequences.

Distinguish numbers and text

Classify values such as age, postcode, phone number and score as number or text depending on their use.

Expected outcome: Reasoned data-type choices.

Create a pixel image model

Design a small grid image using numbered or named colour values and exchange it with another group for reconstruction.

Expected outcome: A working pixel-data model.

Think of sound as data

Represent a simple sequence of changing sound levels as values over time and discuss what the numbers describe.

Expected outcome: A basic measurement model.

Apply simple program rules

Start with stored values and apply rules such as add 2, compare with 10 or join text.

Expected outcome: Correct step-by-step processing.

Find representation errors

Identify examples where data is ambiguous or the wrong type is used and suggest corrections.

Expected outcome: Improved data representation.

Connect input, processing and output

Trace how a small program receives input, stores it, changes it and displays a result.

Expected outcome: A complete process model.

Develop and test your own code system

Create symbols for at least ten items and let another group use the code without extra explanation.

Expected outcome: A tested, documented code.

Create a concept map

Connect information, data, encoding, variable, data type, input, processing and output.

Expected outcome: A coherent summary.

Self-check

I can distinguish information from data.
I can explain why data needs an agreed representation.
I understand text, pixels and sound as forms of digital data.
I can distinguish a number from text that looks like a number.
I can explain variables and simple data types.
I can connect input, storage, processing and output.